• Disease Overview
  • Synonyms
  • Signs & Symptoms
  • Causes
  • Affected Populations
  • Disorders with Similar Symptoms
  • Diagnosis
  • Standard Therapies
  • Clinical Trials and Studies
  • References
  • Programs & Resources
  • Complete Report

Succinic Semialdehyde Dehydrogenase Deficiency

Print

Last updated: August 13, 2020
Years published: 2000, 2002, 2003, 2017, 2020


Acknowledgment

NORD gratefully acknowledges John M. Schreiber, MD, Children’s National Hospital, and Carolyn Hoffman, SSADH Association, for assistance in the preparation of this report.


Disease Overview

Summary

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare inborn error of metabolism that is inherited in an autosomal recessive pattern. In individuals with the disorder, deficient activity of the SSADH enzyme disrupts the metabolism of gamma-aminobutyric acid (GABA). GABA is a natural chemical known as a “neurotransmitter” that serves to inhibit the electrical activities of nerve cells (inhibitory neurotransmitter). SSADH deficiency leads to abnormal accumulation of the compound succinic semialdehyde, which is reduced or converted to 4-hydroxybutyric acid, also known as GHB (gamma-hydroxybutyric acid). GHB is a natural compound that has a wide range of effects within the nervous system. The “hallmark” laboratory finding associated with SSADH deficiency is elevated levels of GHB in the urine (i.e., 4-hydroxybutyric or gamma-hydroxybutyric aciduria), the liquid portion of the blood (plasma), and the fluid that flows through the brain and spinal canal (cerebrospinal fluid [CSF]).

SSADH deficiency leads to various neurological and neuromuscular symptoms and findings. These abnormalities may be extremely variable from person to person, including among affected members of the same families (kindreds). However, most individuals with SSADH deficiency are affected by mild to severe intellectual disability, delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation), and delays in language and speech development. In addition, in some people, initial findings may include diminished muscle tone (hypotonia), an impaired ability to coordinate voluntary movements (ataxia), and/or episodes of uncontrolled electrical activity in the brain (seizures). Some affected individuals may also have additional abnormalities, such as decreased reflex reactions (hyporeflexia); involuntary, rapid, rhythmic eye movements (nystagmus); increased muscular activity (hyperkinesis); and/or behavioral abnormalities.

  • Next section >
  • < Previous section
  • Next section >

Synonyms

  • 4-hydroxybutyric aciduria
  • SSADH deficiency
  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Signs & Symptoms

In individuals with SSADH deficiency, the range, severity, and presentation of certain symptoms and findings may be variable, including among affected family members. In addition, such neurological and neuromuscular symptoms are often considered “nonspecific”, meaning that they may be associated with any number of underlying disorders, potentially leading to difficulties with diagnosis. (For further information, please see the “Standard Therapies: Diagnosis” section of this report below.) However, during childhood, most affected individuals appear to have some degree of delays in the development of certain physical, mental, and behavioral skills that are typically acquired at particular stages (i.e., “developmental milestones”).

Initial or “presenting” symptoms vary from person to person. However, initial symptoms often include delays in achieving certain motor milestones (e.g., crawling, sitting unaided, walking without assistance); reduced muscle tone (hypotonia); and/or intellectual or language delays. In some people, additional presenting symptoms are an impaired ability to coordinate voluntary movements (ataxia); episodes of uncontrolled electrical activity in the brain (seizures); and/or certain abnormalities during early infancy including failure to cry or respond to certain visual stimuli. Although symptoms usually begin during infancy or childhood, the disorder sometimes is not diagnosed until adulthood.

The language and speech abnormalities associated with SSADH deficiency may be extremely variable. For example, in severe cases, individuals may be nonverbal or speech may be infrequent and consist of only a few words or simple phrases but some people have normal speech and language development.

As mentioned above, ataxia or incoordination is sometimes an initial finding associated with SSADH deficiency. The ataxia is typically non-progressive, may be confined to muscles of the trunk and the arms or legs (limbs), and tends to resolve with age.

Some individuals with SSADH deficiency may also develop additional neurological and neuromuscular symptoms. Such abnormalities may include decreased or absent reflex reactions (hyporeflexia or areflexia); abnormally increased muscular activity (hyperkinesis); and/or, less commonly, a movement disorder known as choreoathetosis. This condition is characterized by involuntary, rapid, jerky movements (chorea) occurring in association with relatively slow, sinuous, writhing motions (athetosis). Some affected individuals may also develop behavioral abnormalities, such as unusual irritability, easy agitation or frustration, increasingly aggressive behavior, obsessive compulsive disorder (OCD) or “autistic-like” behaviors. The latter may include impaired communication and social interaction, extreme withdrawal, and/or a tendency to engage in certain ritualistic behaviors or repeated body movements (e.g., frequent rocking).

Additional abnormalities have been reported in association with SSADH deficiency. For example, some individuals may be affected by unusual drowsiness (somnolence); psychotic behaviors, such as the perception of certain sounds, sights, or other sensations in the absence of external stimuli (hallucinations); and/or certain eye (locular) abnormalities. Ocular findings may include involuntary, rapid, rhythmic eye movements (nystagmus); and impaired ability to consciously coordinate movements of the eyes (oculomotor apraxia); and/or poor vision. Some affected individuals have been reported to have abnormalities of the skull and facial (craniofacial) area, including unusual smallness or largeness of the head (microcephaly or macrocephaly).

As mentioned above, non-progressive ataxia associated with SSADH deficiency may tend to significantly improve with age. In addition, evidence suggests that there may be additional variations with age seen in associated symptoms. For example, whereas some younger individuals may tend to be affected by drowsiness (somnolence), older individuals may be more likely to develop abnormally increased activity (hyperactivity) or aggressive behaviors.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Causes

SSADH deficiency is a rare inborn error of metabolism that is inherited in an autosomal recessive pattern. “Metabolism” refers to all the chemical processes in the body, including the breakdown of complex substances into simpler ones (catabolism), usually with the release of energy, and processes in which complex substances are built up from simpler ones (anabolism), usually resulting in energy consumption. Inborn errors of metabolism result from abnormal functioning of a specific protein or enzyme that accelerates particular chemical activities in the body.

Most genetic diseases are determined by the status of the two copies of a gene, one received from the father and one from the mother. Recessive genetic disorders occur when an individual inherits two copies of an abnormal gene for the same trait, one from each parent. If an individual inherits one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms. The risk for two carrier parents to both pass the altered gene and have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents is 25%. The risk is the same for males and females.

Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.

The gene responsible for most cases of SSADH deficiency is ALDH5A1 that codes for the SSADH enzyme. Evidence suggests that most affected families have had different changes (mutations) of the SSADH gene that leads to impaired functioning of the SSADH enzyme.

Impaired functioning of the SSADH enzyme results in disrupted metabolism of GABA (gamma-aminobutyric acid), an amino acid neurotransmitter. Amino acids are the chemical building blocks that form proteins in the body. Neurotransmitters modify or result in the transmission of nerve impulses from one nerve cell (neuron) to another, enabling neurons to communicate. More specifically, these natural chemicals either serve to trigger or inhibit the electrical activities of “targeted” neurons (i.e., excitatory or inhibitory neurons). GABA is the main inhibitory neurotransmitter in the brain.

SSADH deficiency leads to abnormal accumulation of the compound succinic semialdehyde, which is converted to 4-hydroxybutyric acid (4-HBA) or “GHB” (gamma-hydroxybutyric acid). Thus, individuals with SSADH deficiency have unusually elevated levels of GHB in urine, plasma, and cerebrospinal fluid. As mentioned above, GHB is a natural compound that has a wide range of affects within the nervous system (i.e., neurophysiologic effects). Although there is evidence that it acts as a neurotransmitter, its specific functions in the brain remain unknown.

In the 1960s, GHB was developed by the pharmaceutical industry as an agent similar to GABA (analog). It was initially used as an anesthetic for children due to its sedative properties; however, such use resulted in adverse side effects. More recently, evidence suggests that GHB plays an important role in energy regulation and as a “protector” against tissue damage (e.g., during lack of adequate oxygen supply to tissues [hypoxia]). Its current clinical application is in the treatment of cataplexy, part of a sleep disorder known as narcolepsy, though it has also been used for alcohol-withdrawal syndrome and difficult labor and delivery during childbirth.

Certain effects potentially associated with the therapeutic use of GHB (i.e., pharmacologic effects) are similar to those seen in individuals with SSADH deficiency. These include diminished muscle tone (hypotonia), drowsiness (somnolence), and seizures or seizure-like activity. In addition, reports suggest that in some affected individuals, there may be age-related decreases of GHB concentrations in bodily fluids, potentially leading to the symptom variations seen in some cases. For example, younger individuals with relatively high GHB concentrations in bodily fluids may tend to be affected by drowsiness. In contrast, in older individuals with lower GHB concentrations, symptoms may tend to include abnormally increased activity or aggressive behaviors. Based upon such findings, some investigators suggest that GHB may act on inhibitory nerve cell (neuron) receptors at high concentrations and excitatory receptors at low concentrations. (Receptors are specific sites on the surface of a neuron that bind with neurotransmitters.) Furthermore, SSADH deficiency results in a decrease in GABA receptors in early life, also likely contributing to the shift towards more excitation.

Further research is required to learn more about GHB’s mode of action and to determine whether the neurological symptoms associated with SSADH deficiency result from increased accumulations of GHB, disturbances of GABA levels, a combination of both, or other abnormalities.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Affected populations

SSADH deficiency appears to affect males and females relatively equally. Since the disorder was originally described in 1981 (C. Jakobs), over 400 cases of SSADH deficiency have been identified. According to one review published in 1997 reporting 23 affected individuals (from 20 families), the age at diagnosis ranged from three months to 25 years. Most affected individuals were of Turkish, American Caucasian, Indian, and Northern European descent. Additional nationalities were also noted, including Korean, Palestinian, Syrian, Pakistani, Saudi, Chinese, and Inuit descent. A recent review of adult cases included one with long-standing intellectual disability diagnosed with SSADH deficiency at 63 years old when he had a progressive decline of function and increased seizures.

Due to the variability and nonspecific nature of associated symptoms, experts suggest that the disorder may be significantly underdiagnosed. As a result, it is difficult to determine the true frequency of SSADH deficiency in the general population.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Diagnosis

The diagnosis of SSADH deficiency is usually made after birth (postnatally) during infancy or childhood (or, in some cases, adulthood), based upon a thorough clinical evaluation, identification of characteristic physical findings, and a variety of specialized tests. Due to the nonspecific nature and variability of associated symptoms, experts suggest that SSADH deficiency should be considered in any individuals with two or more features of intellectual, language, and motor delay and abnormally diminished muscle tone (hypotonia) of unknown cause (idiopathic). Specialized testing to confirm a diagnosis of SSADH deficiency typically includes studies (i.e., quantitative organic acid analysis in an appropriate specialist laboratory) that may detect increased concentrations of 4-hydroxybutyric acid (4-HBA) in urine (i.e., 4-hydroxybutyric aciduria) and testing to confirm deficient activity of the SSADH enzyme in white blood cells (leukocytes) isolated from whole blood. (Note: As mentioned above, increased concentrations of 4-HBA may also be detected in plasma and cerebrospinal fluid. In addition, deficient SSADH activity has also been demonstrated in certain cells other than leukocytes.)

Molecular genetic testing to identify bi-allelic mutations (abnormal changes found on both copies of a gene) or deletions in the ALDH5A1 gene is increasingly used to make or confirm a diagnosis of SSADH deficiency.

Physicians who are interested in obtaining information on testing for SSADH deficiency may wish to contact:

K. M. Gibson, PhD, FACMG
Allen I. White Professor and Chair
Experimental and Systems Pharmacology (ESP)
WSU College of Pharmacy
PBS Building Room 347
412 E. Spokane Falls Blvd
Spokane WA 99202-2131
509 358 7954
mike.gibson@wsu.edu

In some instances, other specialized tests may also be conducted to help detect or characterize certain abnormalities that may be associated with the disorder. Such testing may include computerized tomography (CT) scanning, magnetic resonance imaging (MRI), or electroencephalography (EEG). During CT scanning, a computer and x-rays may be used to create a film showing cross-sectional images of the brain. In MRI, a magnetic field and radio waves may create detailed cross-sectional images of the brain. An EEG is conducted to record the brain’s electrical impulses, potentially detecting brain wave patterns that are characteristic of certain types of seizures.

In some cases, a diagnosis of SSADH deficiency may be suggested before birth (prenatally) by specialized tests. These include studies that may detect increased concentrations of 4-ydroxybutyric acid (GHB) in fluid surrounding the developing fetus (amniotic fluid) and deficient activity of the SSADH enzyme in certain fetal cells obtained via amniocentesis or chorionic villus sampling (CVS). During amniocentesis, a sample of fluid that surrounds the fetus is removed and analyzed, whereas CVS involves the removal of tissue samples from a portion of the placenta.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Standard Therapies

Treatment
The treatment of SSADH deficiency is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; physicians who specialize in the diagnosis and treatment of neurological disorders in children (pediatric neurologists); and/or other health care professionals.

In some affected individuals, treatment may include the use of certain medications to help prevent, reduce, or control seizures (anticonvulsants, e.g., carbamazepine, levetiracetam, etc.) or to alleviate other symptoms potentially associated with the disorder. (For further information, please see the “Investigational Therapies” section of this report below). A variety of anti-seizure medications are utilized. While valproic acid may reduce residual SSADH enzyme activity, it may sometimes be considered in cases with refractory seizures.

Early intervention may be important in ensuring that children with SSADH deficiency reach their potential. Special services that may be beneficial include physical therapy, special remedial education, speech therapy, occupational therapy and other medical, social, and/or vocational services.

Genetic counseling is recommended for affected individuals and their families. Other treatment is symptomatic and supportive.

Patients, families and physicians interested in obtaining clinical and/or therapeutic information on SSADH deficiency may wish to contact:

Phillip L. Pearl, MD
Chief of Epilepsy and Clinical Neurophysiology
Boston Children’s Hospital
Harvard Medical School
Phillip.Pearl@childrens.harvard.edu

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Clinical Trials and Studies

Vigabatrin is an anti-seizure medication that decreases the formation of succinic semialdehyde and is therefore, in theory, an exciting treatment option for SSADH deficiency. However, clinical experience has been mixed.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov.
All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Toll-free: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/

For information about clinical trials sponsored by private sources, in the main, contact:
www.centerwatch.com

For more information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

References

TEXTBOOKS
Pearl PL and Gibson KM. Succinic Semialdehyde Dehydrogenase Deficiency. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:499.

Lyon G, et al., eds. Neurology of Hereditary Metabolic Diseases in Childhood. 2nd ed. New York, NY: McGraw-Hill Companies, Inc.; 1996:86.

Scriver CR, et al., eds. The Metabolic and Molecular Basis of Inherited Disease. 7th ed. New York, NY: McGraw-Hill Companies, Inc.; 1995:1360-1361.

Buyse ML. Birth Defects Encyclopedia. Dover, MA: Blackwell Scientific Publications, Inc.; 1990:17-18.

REVIEW ARTICLES
Lapalme-Remis S, Lewis EC, De Meulemeester C, Chakraborty P, Gibson KM, et al., Natural history of succinic semialdehyde dehydrogenase deficiency through adulthood. Neurology. 2015 Sep 8;85(10):861-865.

Pearl PL, Parviz M, Vogel K, Schreiber J, Theodore WH, Gibson KM. Inherited disorders of gamma-aminobutyric acid metabolism and advances in ALDH5A1 mutation identification. Dev Med Child Neurol. 2014 Dec 29 [Epub ahead of print].

Vogel KR, Pearl PL, Theodore WH, McCarter RC, Jakobs C, Gibson KM. Thirty years beyond discovery – clinical trials in succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. J Inherit Metab Dis. 2013 May; 36(3): 401-410.

Pearl PL, Gibson KM, Cortez MA, Wu Y, Carter Snead O 3rd, Knerr I, Forester K, Pettiford JM, Jakobs C, Theodore WH. Succinic semialdehyde dehydrogenase deficiency: lessons from mice and men. J Inherit Metab Dis. 2009 Jun;32(3):343-352.

Ina Knerr, MD, K. Michael Gibson, PhD, Cornelis Jakobs, PhD, and Phillip L. Pearl, MD
Neuropsychiatric Morbidity in Adolescent and Adult Succinic Semialdehyde Dehydrogenase Deficiency Patients, CNS Spectr. 2008 Jul;13(7):598–605.

Kuhara T. Diagnosis of inborn errors of metabolism using filter paper urine, urease treatment, isotope dilution and gas chromatography-mass spectometry. J Chromatogr B Biomed Sci Appl. 2001;758;3-25.

Medina-Kauwe LK, Tobin AJ, De Meirleir L, et al. 4-Aminobutyrate aminotransferase (GABA-transaminase) deficiency. J Inherit Metab Dis. 1999;22:414-27.

Gibson KM, et al. 4-Hydroxybutyric acid and the clinical phenotype of succinic semialdehyde dehydrogenase deficiency, an inborn error of GABA metabolism. Neuropediatrics. 1998;29:14-22.

JOURNAL ARTICLES
Didiášová M, Banning A, Brennenstuhl H, et al. Succinic semialdehyde dehydrogenase deficiency: an update. Cells 2020;9:477.

DiBacco ML, Roullet JB, Kapur K, et al. Age-related phenotype and biomarker changes in SSADH deficiency. Ann Clin Transl Neurol. 2018;6:114-120.

Vogel KR, Ainslie GR, Gibson KM. mTOR inhibitors rescue premature lethality and attenuate dysregulation of GABAergic/glutamatergic transcription in murine succinate semialdehyde dehydrogenase deficiency (SSADHD), a disorder of GABA metabolism. J Inherit Metab Dis. 2016 Nov;39(6):877-886.

Schreiber JM, Pearl PL, Dustin I, Wiggs E, Barrios E, Wassermann EM, Gibson KM, Theodore WH. Biomarkers in a taurine trial for succinic semialdehyde dehydrogenase deficiency. JIMD Rep. 2016;30:81-87.

Pearl PL, Schreiber J, Theodore WH, McCarter R, Barrios ES, Tyu J, Wiggs E, He J, Gibson KM. Taurine trial in succinic semialdehyde dehydrogenase deficiency and elevaed CNS GABA. Neurology. 2014 Mar 18;82(11):940-944.

Epilepsy in succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. Brain Dev. 2011 Oct;33(9):796-805.

Pearl PL, Gibson KM, Quezado Z, Dustin I, Taylor J, Trzcinski S, Schreiber J, Forester K, Reeves-Tyer P, Liew C, Shamim S, Herscovitch P, Carson R, Butman J, Jakobs C, Theodore W. Decreased GABA-A binding on FMZ-PET in succinic semialdehyde dehydrogenase deficiency. Neurology. 2009 Aug 11;73(6):423-429.

Pearl PL, et al., Succinic semialdehyde dehydrogenase deficiency in children and adults. Ann Neurol. 2003;54:S73-80.
Gropman A, Vigabatrin and newer interventions in succinic semialdehyde dehydrogenase deficiency. Ann Neurol. 2003;54:S66-72.

Gupta M, Greven R, Jansen EE, et al. Therapeutic intervention in mice deficient for succinate semialdehyde dehydrogenase (gamma hydroxybutyric aciduria). J PharmacolExpTher. 2002;302:180-87.

Hogema BM, Gupta M, Senephransiri H, et al. Pharmacologic rescue of lethal seizures in mice deficient in succinate semialdehyde dehydrogenase. Nat Genet. 2001;29:212-16.

Hogema BM, Akaboshi S, Taylor M, et al. Prenatal diagnosis of succinic semialdehyde dehydrogenase deficiency: increased accuracy employing DNA, enzyme, and metabolic analyses. Mol Genet Metab. 2001;72:218-22.

Peters H, Cleary M, Boneh A. Succinic semialdehyde dehydrogenase deficiency in siblings: clinical heterogeneity and response to early treatment. J Inherit Metab Dis. 1999;22:198-199.

Gibson KM, Sweetman L, Kozich V, et al. Unusual enzyme findings in five patients with metabolic profiles suggestive of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria). J Inherit Metab Dis. 1998;21:255-261.

Chambliss KL, Hinson DD, Trettel F, et al. Two exon-skipping mutations as the molecular basis of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria). Am J Hum Genet. 1998;63:399-408.

Gibson KM, Doskey AE, Rabier D, et al. Differing clinical presentation of succinic semialdehyde dehydrogenase deficiency in adolescent siblings from Lifu Island, New Caledonia. J Inherit Metab Dis. 1997;20:370-374.

Gibson KM, Christensen E, Jakobs C, et al. The clinical phenotype of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria): case reports of 23 new patients. Pediatrics. 1997;99:567-574.

Trettel F, Malaspina P, Jodice C, et al. Human succinic semialdehyde dehydrogenase: molecular cloning and chromosomal localization. AdvExp Med Biol. 1997;414:253-260.

Matern D, Lehnert W, Gibson KM, et al. Seizures in a boy with succinic semialdehyde dehydrogenase deficiency treated with vigabatrin (gamma-vinyl-GABA). J Inherit Metab Dis. 1996;19:313-318.

Peters H, Cleary M, Boneh A. Succinic semialdehyde dehydrogenase deficiency in siblings: clinical heterogeneity and response to early treatment. J Inherit Metab Dis. 1999;22:198-199.

Gibson KM, Hoffmann GF, Hodson AK, et al. 4-Hydroxybutyric acid and the clinical phenotype of succinic semialdehyde dehydrogenase deficiency, an inborn error of GABA metabolism. Neuropediatrics. 1998;29:14-22.

Gibson KM, Sweetman L, Kozich V, et al. Unusual enzyme findings in five patients with metabolic profiles suggestive of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria). J Inherit Metab Dis. 1998;21:255-261.

Chambliss KL, Hinson DD, Trettel F, et al. Two exon-skipping mutations as the molecular basis of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria). Am J Hum Genet. 1998;63:399-408.

Gibson KM, Doskey AE, Rabier D, et al. Differing clinical presentation of succinic semialdehyde dehydrogenase deficiency in adolescent siblings from Lifu Island, New Caledonia. J Inherit Metab Dis. 1997;20:370-374.

Gibson KM, Christensen E, Jakobs C, et al. The clinical phenotype of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria): case reports of 23 new patients. Pediatrics. 1997;99:567-574.

Trettel F, Malaspina P, Jodice C, et al. Human succinic semialdehyde dehydrogenase: molecular cloning and chromosomal localization. AdvExp Med Biol. 1997;414:253-260.

Matern D, Lehnert W, Gibson KM, et al. Seizures in a boy with succinic semialdehyde dehydrogenase deficiency treated with vigabatrin (gamma-vinyl-GABA). J Inherit Metab Dis. 1996;19:313-318.

Jakobs C, Ogier H, Rabier D, et al. Prenatal detection of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria) [letter]. Prenatal Diag. 1993;13:150.

INTERNET
Pearl PL, Wiwattanadittakul N, Roullet JB, et al. Succinic Semialdehyde Dehydrogenase Deficiency. 2004 May 5 [Updated 2016 Apr 28]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1195/ Accessed August 11, 2020.

  • < Previous section
  • Next section >

Programs & Resources

RareCare® Assistance Programs

NORD strives to open new assistance programs as funding allows. If we don’t have a program for you now, please continue to check back with us.

Additional Assistance Programs

MedicAlert Assistance Program

NORD and MedicAlert Foundation have teamed up on a new program to provide protection to rare disease patients in emergency situations.

Learn more https://rarediseases.org/patient-assistance-programs/medicalert-assistance-program/

Rare Disease Educational Support Program

Ensuring that patients and caregivers are armed with the tools they need to live their best lives while managing their rare condition is a vital part of NORD’s mission.

Learn more https://rarediseases.org/patient-assistance-programs/rare-disease-educational-support/

Rare Caregiver Respite Program

This first-of-its-kind assistance program is designed for caregivers of a child or adult diagnosed with a rare disorder.

Learn more https://rarediseases.org/patient-assistance-programs/caregiver-respite/

Patient Organizations


National Organization for Rare Disorders